'Reliable' in the Bible

because if the message spoken by angels was reliable, and every violation and act of disobedience received its just punishment,

Let us seize and hold tightly the confession of our hope without wavering, for He who promised is reliable and trustworthy and faithful [to His word];

By faith even Sarah herself received the ability to conceive [a child], even [when she was long] past the normal age for it, because she considered Him who had given her the promise to be reliable and true [to His word].